A very skilled basketball player at South Philadelphia High School, Rosenberg was approached by many prep schools in south Philly, but lacked the credits to be eligible. Despite being from a poor family, Petey's father was finally able to get him into Brown Prep. He went to St. Joseph's, but left school to play professionally with the SPHA's. After many years with the club, he moved to the Warriors in the BAA for one season, where the Warriors won the championship. He also served in the U.S. Army during World War 2, stationed in the Pacific. After basketball, he operated a steak shop in south Philly, and also managed a trucking company. He died of heart and kidney failure in 1997.